Lycopene, a protective substance in tomatoes, lowers blood pressure. Chinese researchers, affiliated with Soochow University, conclude this in a meta-study that has appeared in Nutrients. The dosage in which lycopene lowers blood pressure is so small that drinking a glass of tomato juice daily should have an effect.

Study
The researchers traced 6 previously published studies in which researchers had given lycopene supplements to test subjects. They combined the results of the research and re-analyzed them.

Results
Lycopene had no effect on the diastole, the blood pressure between two heartbeats. But it did have an effect on the systolic blood pressure during the contraction of the heart muscle. According to the meta-study systolic blood pressure dropped by 5 points.

When the researchers split their data, they saw that the blood pressure lowering effect of lycopene on blood pressure was stronger in Asians than in othet ethnic groups. It was also stronger when the blood pressure before supplementation was higher.

Dosage also a role as well. Doses higher than 12 milligrams per day were more effective than lower doses.

The figure below has been simplified. Click it for the full version.

The highest dose tested in the analyzed studies was 15 milligrams per day. And that's when things get really interesting, because there is much more lycopene in many everyday foods. If a 15-milligram lycopene pill reduces blood pressure per day, a glass of tomato juice per day may have a lot more effect.

Conclusion
"In conclusion, our meta-analysis provides evidence of the role of lycopene in lowering systolic blood pressure", write the researchers. "Longer term studies with a larger number of patients are required."

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